Interpolative variable-speed repetitive control and its application to a deburring robot with cutting load control

Abstract

Usual methods of repetitive control, when applied to path control of robots, cannot cope with dynamic path speed changes, which correspond to changes in the reference period. This paper proposes a modified repetitive control method that achieves feedforward control by switching the waveforms previously stored in several controllers according to speed changes, in an interpolating manner if necessary. An algorithm to implement the proposed method for robots is developed, and a deburring robot is constructed which changes its path speed according to the cutting load, which is detected by the variation of tool revolution speed. Experimental results with test models show that the method can significantly reduce errors, even when the speed changes, and helps to improve the accuracy of robots.